1. Field of the Invention
The present invention relates to an image forming apparatus for being mounted on a vehicle, and more particularly to a fixing structure for fixing an exposure unit of an image forming apparatus to and releasing the exposure unit from a vehicle, the image forming apparatus having a vibration isolation structure for suppressing vibration transmitted from the vehicle.
2. Description of the Related Art
There have heretofore been known image forming apparatus for recording radiation image information of a subject such as a human body on a stimulable phosphor sheet having a stimulable phosphor layer. A stimulable phosphor is a phosphor which, when exposed to an applied radiation (X-rays, α-rays, β-rays, γ-rays, electron beams, ultraviolet radiation, or the like), stores part of the energy of the radiation, and, when subsequently exposed to applied stimulating rays such as visible light, emits photostimulated luminescence in proportion to the stored energy of the radiation.
An image forming apparatus disclosed in Japanese Laid-Open Patent Publication No. 2001-299743 is installed on a vehicle such as a mobile medical examination car and mounted on the chassis of the mobile medical examination car. The disclosed image forming apparatus can take pictures of subjects for medical examination within the vehicle and at remote sites.
Generally, image forming apparatus for use on vehicles have optical systems that are subject to vibrations. For example, Japanese Laid-Open Patent Publication No. 2001-299743 discloses an image forming apparatus comprising a medical image scanner for scanning patient's bodies. When the image forming apparatus is installed on a vehicle, the optical system thereof is subject to vibrations from the wheels of the vehicle while the vehicle is being driven or vibrations from the engine or electric generator on the vehicle, and may tend to decrease in function.
Heretofore, the image forming apparatus for use on vehicles have not been equipped with a vibration suppressing mechanism for blocking vibrations from being applied from the vehicle to the optical system. Consequently, since the optical system decreases more in function as the resolution of the image forming unit of the image forming apparatus for reading images is higher, it has been difficult to install highly accurate image forming apparatus on vehicles.
Japanese Laid-Open Patent Publication No. 10-246999 discloses a structure for fixing an image forming apparatus to a floor to prevent it from falling by an engaging member mounted on a plate disposed on the floor and held in engagement with a plurality of engaged members on a lower portion of the image forming apparatus.
However, Japanese Laid-Open Patent Publication No. 10-246999 discloses or suggests nothing about a vibration suppressing mechanism for blocking vibrations from being applied from the vehicle to the optical system mounted on the vehicle.
The applicant of the present application has proposed a vibration isolation mechanism mounted on a support post fixed to a vehicle and a holder holding an exposure unit having an optical system through the vibration isolation mechanism. The vibration isolation mechanism holds the holder to prevent vibrations from being transmitted from the vehicle to the exposure unit.